A device which includes a coupler and which performs proximity wireless communication with a different device has been known. When two devices become proximate and are in a communication range, the coupler is electromagnetically coupled to a coupler of the other device. By the coupling, the two devices can transmit/receive a signal to/from each other in a wireless manner.
The coupler may be provided in a communication device such as a card device. For example, when the card device is inserted into a card slot of an electronic device, the electronic device can perform, with a coupler, proximity wireless communication.
When couplers of the two communication devices become proximate to each other, characteristics of the couplers may be decreased.